One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10)(11,12)(13,17)(14,15)(16,20)(18,19)(21,22)(23,24)(25,26,32,37)(27,38,31,33)(28,36,30,34)(29,35,40,39)(1,2)(3,5)(4,6)(7,8)(25,27,32,31)(26,33,37,38)(28,35,30,39)(29,34,40,36)(10,15)(11,16)(17,22)(18,23)(25,28,32,30)(26,34,37,36)(27,39,31,35)(29,38,40,33)(9,11,14,16)(10,12,15,20)(13,18,21,23)(17,19,22,24)(25,29,32,40)(26,35,37,39)(27,34,31,36)(28,33,30,38)(1,3,4,7)(2,5,6,8)(9,12)(10,16)(11,15)(13,19)(14,20)(17,23)(18,22)(21,24)(25,30,32,28)(26,36,37,34)(27,39,31,35)(29,38,40,33)(9,13,14,21)(10,17,15,22)(11,18,16,23)(12,19,20,24)(25,31,32,27)(26,33,37,38)(28,35,30,39)(29,36,40,34)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.